<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>异步</title>
</head>

<body>
    <script>
        function a() {
            setTimeout(function () {
                console.log('菜做完了');
            }, 1000)
        }

        a()

        function b() {
            console.log('玩手机');
        }
        b()
    </script>
</body>

</html>